This invention relates to determining the integrity of splices in optical fibers, and more particularly to a method for measuring splice loss that may be practiced solely at the location of the splice.
Method and apparatus for measuring the insertion loss of a splice between one ends of a pair of optical fibers are described in the article "Hot Splices of Optical Waveguide Fibers" by Y. Kohanzadeh, Applied Optics, March, 1976/Vol. 15, No. 3, pages 793-795. In accordance with the reference, splice loss is defined as EQU 10 log (1-P.sub.s /P.sub.O) (1)
where P.sub.s is a measure of light scattered from the splice and P.sub.O is a measure of light transmitted in the input fiber and incident on the splice. Such a splice loss measurement technique has particular advantage in field applications since it can be practiced solely at the location of the splice. More specifically, it does not require access to he other ends of the fibers, which may be spaced many kilometers from the splice. Applicants have recently discovered that in many instances such an indication of splice loss, which only utilizes a measurement of light scattered frowm the splice itself, is not an accurate indication of the true splice loss and the integrity of the splice. An object of this invention is the provision of an improved method of measuring splice loss that may be practiced solely at the location of the splice.